Neural innervation determines appropriate contractility of the detrusor muscle in the bladder. When appropriately innervated, the bladder is compliant and can hold variable volumes of urine at low pressures. Failure of the bladder to modulate internal pressures results in transfer of high pressures to the kidney with subsequent glomerular damage;thus, patients with neurogenic bladder disease are at high risk for renal failure and renal transplantation. Spina bifida is the most common etiology of pediatric neurogenic bladder. The association between neural tube defects and bladder dysfunction as well as the neural crest (NC) origin of sympathetic and parasympathetic inputs that innervate the bladder implies that NC derivatives are essential participants in normal bladder development. Anatomical and immunohistochemical studies of bladder innervation have identified neural components and some of the neurotransmitter subtypes that are present in late fetal and postnatal development. However, a comprehensive understanding of bladder cell types that derive from NC is lacking. Identification of NC lineages and genes that control their differentiation within the bladder is of significant relevance to understanding the etiology and potential treatments for neurogenic bladder. In vitro neural crest stem cells give rise to neurons, glia and myofibroblasts. A critical question that remains to be addressed is whether only bladder innervation is NC-derived or if neural crest stem cells also contribute to additional lineages in this organ. Because deficiencies of bladder smooth muscle have been reported in fetuses with myelomeningocele, the relationship between NC and smooth muscle differentiation is of particular interest. We will test the hypothesis that multiple lineages within the bladder are NC-derived by analysis of engineered mouse models throughout ontogeny of the bladder. We have implemented BAG recombination methods that enable tracing of neural crest stem cells expressing SoxlO. Aim 1 will establish a temporal profile of NC migration into the bladder and define co-localization of lineage markers in the bladder with SoxlO transgene expression. Aim 2 will comprehensively identify NC- derived cell types in the bladder by implementing Cre-/oxP fate mapping. In Aim 3 we will capture neural crest stem cells from the developing bladder to define temporal changes in developmental potential and identify transcriptional profiles specific to sacral NC. Aim 4 will define mechanisms of altered NC development in myelodysplastic bladders of mouse spina bifida models. Our analysis will pioneer exploration of NC lineages pathways in the bladder, identify candidate genes for future analysis of disease alleles in neurogenic bladder patients and begin to define mechanisms of altered NC development in spina bifida mouse models. The proposed studies directly address multiple needs for basic research in bladder development as stated in the "Strategic Plan for Pediatric Urology" and are responsive to the objectives of the "Basic Research in the Bladder and Lower Urinary Tract" Program Announcement.